Packaging Code For Aws Lambda

I am trying to package code for AWS Lambda. Lambda has various restrictions, such as using Node 6.10, and not having a build step, like AWS EB does. I also am using NPM modules, so

Solution 1:

You can use serverless with serverless-webpack

Then you deploy your bundle with serverless deploy

Solution 2:

It turns out that this is possible, but it requires some tricky configuration to achieve. I have created a boiler-plate repo for others to use.

Here are the important bits...

First, you need a .babelrc that targets Node.js 6.10:

{"presets":[["env",{"targets":{"node":"6.10"},"loose":false,"spec":true}]]}

Next, you need to configure Webpack to generate a commonjs library targetting node:

const path = require('path');
const webpack = require('webpack');

const debug = process.env.NODE_ENV !== 'production';

module.exports = {
  context: __dirname,
  entry: [ 'babel-polyfill', './index.js' ],
  output: {
    path: path.join(__dirname, 'out'),
    filename: 'index.js',
    libraryTarget: 'commonjs'
  },
  devtool: debug ? 'source-map' : false,
  module: {
    rules: [
      {
        test: /\.js$/,
        use: {
          loader: 'babel-loader',
          options: {
            babelrc: true,
            compact: !debug
          }
        }
      }
    ],
  },
  target: 'node',
  plugins: [
    new webpack.DefinePlugin({ 'global.GENTLY': false })
  ]
};

Note that you do not want to ignore the node_modules folder, since that would prevent static-linking.

The babel-polyfill plugin is also crucial if you want to use modern JS features.

Your actual handler code should have a named export that matches what you have set in the AWS console:

exportconsthandler = (event, context, callback) => callback(null, 'OK');

Do not do it like this!

// Bad! exportdefault {
  handler: (event, context, callback) =>callback(null, 'OK'),
};

When packaging the code, make sure you add index.js to the top level of the zip:

zip -j bundle.zip ./out/index.js